Investigation of Arctic ozone depletion sampled over midlatitudes during the Egrett campaign of spring/summer 2000

• Main Authors: Ross, D. E. M., Pyle, J. A., Harris, N. R. P., Mcintyre, J. D., Millard, G. A., Robinson, A. D., Busen, R.
• Other Authors: Centre for Atmospheric Science Cambridge, UK, University of Cambridge UK (CAM), Atmospheric Chemistry Modelling Support Unit Cambridge (ACMSU), National Centre for Atmospheric Science Leeds (NCAS), Natural Environment Research Council (NERC)-Natural Environment Research Council (NERC), European Ozone Research Coordinating Unit Cambridge (EORCU), Deutsches Zentrum für Luft- und Raumfahrt (DLR)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Arctic
• Online Access: https://hal.science/hal-00295490; https://hal.science/hal-00295490/document; https://hal.science/hal-00295490/file/acp-4-1407-2004.pdf

International audience A unique halocarbon dataset has been obtained using the Australian high altitude research aircraft, the Grob G520T Egrett, during May-June 2000 with GC instrument (DIRAC), which has been previously deployed on balloon platforms. The halocarbon data generally shows a good anticorrelation with ozone data obtained simultaneously from commercial sensors. On 5 June 2000, at 380K, the Egrett entered a high latitude tongue of air over the U.K. CFC-11 and O 3 data obtained on the flight show evidence of this feature. The dataset has been used, in conjunction with a 3D chemical transport model, to infer ozone depletion encountered in the midlatitude lower stratosphere during the flight. We calculate that ozone is depleted by 20% relative to its winter value in the higher latitude airmass. A suite of ozone loss tracers in the model have been used to track ozone depletion according to location relative to the vortex and chemical cycle responsible. The model, initialised on 9 December, indicates that 50% of the total chemical ozone destruction encountered in June in the middle latitudes occurred in the 90-70°N equivalent latitude band and that 70% was due to halogen chemistry.